I can hear below 10Hz - am I abnormal?

2018-06-25 10:08:41

I often read that the limits of human hearing is 20Hz–20kHz. To me, this "fact" seems quite ridiculous.

Surely everyone can hear tones below 20Hz? The buzz of machines like refrigerators? The hum of traffic? Airplanes, etc? Most urban areas are saturated with these irritating frequencies, and I hear them all day long. Am I really so unusual?

If I play 20Hz in Audacity, it's very loud, clear, and easily perceived. It fades in strength as I go down through the teens, down to 9Hz, which is feint, but I can definitely still hear it. I wasn't able to hear 8Hz, but I was listening in a noisy environment and haven't done much testing. Plus, my ears are pretty blocked up with wax and I have tinnitus, so I wouldn't say my hearing was good anyway.

At the upper end, I can't hear much above 10Hz. So to me, the claim that humans can hear 20Hz–20kHz seems perfectly correct if you halve it!

Re: I can hear below 10Hz - am I abnormal?

What are you listening on? You're probably hearing harmonic distortion. Generate a sweep here https://www.audiocheck.net/audiofrequencysignalgenerator_sweep.php below the range you think you can hear to 3khz or more, with the volume set at an everyday level. Play around with other tests at that site. 20hz isn't hard and fast but it's generally pretty close to the limit.

Re: I can hear below 10Hz - am I abnormal?

I don't think I'm hearing harmonic distortion because when I listen to tones down to 20Hz, they continue to get lower, and when I go below 20Hz, they still continue to get lower. I think I can tell the difference between 10Hz and higher frequencies.

Re: I can hear below 10Hz - am I abnormal?

I don't think I'm hearing harmonic distortion because when I listen to tones down to 20Hz, they continue to get lower, and when I go below 20Hz, they still continue to get lower. I think I can tell the difference between 10Hz and higher frequencies.

My hunch is that when the "20 Hz" was "agreed upon", it was a lower bound for usable frequency. (Hard to make anything usable when you couldn't reproduce to get any use of it without feeling it in your gut more than hearing it with your ears, but with IEMs you can.) 20 to 20k "looks like a nice rule" too. Very scientific ;-)

Re: I can hear below 10Hz - am I abnormal?

My IEMs can do <10Hz as well, they touch my ear canals directly and I can even count the vibrations per second, somewhat similar to touching the diaphragm of a speaker and feel the vibration even when the sound itself is inaudible.

Re: I can hear below 10Hz - am I abnormal?

My hunch is that when the "20 Hz" was "agreed upon", it was a lower bound for usable frequency.

I've always assumed it was some kind of "average" of people with "normal hearing". Some (young) people can hear above 20kHz and I assume some people can hear below 20Hz. As you probably know, some people have better than 20/20 vision too. The true average wouldn't go up to 20kHz because much of the population is older (like me) with some loss of high frequencies and that would push-down the average. The "95th percentile" is pretty common in statistics, so maybe 5% of the population can hear beyond the traditional 20-20kHz range.

That 20-20klhz range probably includes "pitch" that's felt in the body...

I don't think I can hear that low. ( I know I can't hear 20kHz.) I don't have IEMs. With headphones I can sometimes feel the headphones vibrating on my head but usually I hear distortion/rattling too. With speakers it's hard to say because at live concerts or with the a good subwoofer cranked-up I'm certainly feeling the low frequencies in my chest and the feeling-vibration in the body dominates to the point that I don't know if I'm "hearing" those low frequencies with my ears or not. You cannot get the same experience with headphones or IEMs.

And of course, you can perceive air pressure changes in your ears down to nearly zero Hz when you drive up or down a mountain or fly up or down in a plane or if you go under water. I'm sure you can feel 1Hz as a pressure change and you should be able to count the cycles, but it's not sound.

But... I guess "hearing" and "sound" aren't whole point. When I crank-up the speakers I want to feel the bass... That's one of the reasons I prefer speakers over headphones.

As a point of reference, the lowest note on a standard bass guitar is about 40Hz. That's mostly felt and most of what you hear is the harmonics. A kick drum might go lower than that, organs (particularly pipe organs) can go below that. A piano goes lower than that too, but the harmonics dominate and it doesn't "seem like" you're getting the kind of deep bass from a piano that you can get from a kick drum or bass guitar. Movie sound effects can go as low as the producer wants, but I assume most of the energy exists in a band that's better-perceived and more easily reproduced.

Re: I can hear below 10Hz - am I abnormal?

@DVDdoug: Although a bass guitar has lots of harmonics, and people have been arguing over whether you actually hear the fundamental of Adler's "Subcontra" bass guitar's C#0 at 17 Hz, there are musicians who use bass tones much closer to a sine.

Play it with a spectrum analyzer on. Not too loudly at first listen. * Just after 2:40: a sweep from 10 Hz to thirtysomething and down to 30. That is the peak for half a minute.* Then down to 24-ish and down to 19. Barely audible in my room. * The 19 drones until just after 5 minutes and sweeps slightly up to an F0 at 22 Hz. That is a powerful tone in my room even at modest levels. * Then a sweep up to 100 and down to a loud 40. (There is a 51 Hz tone there too, but it is, like, 20 dB lower.) The 40 Hz tone runs past the nine minute mark. Forty Hz isn't that low. * Just before 10:30, the peak is at that infamous C0# at 17 Hz. Not audible in my room.

Re: I can hear below 10Hz - am I abnormal?

I don't think I'm hearing harmonic distortion because when I listen to tones down to 20Hz, they continue to get lower, and when I go below 20Hz, they still continue to get lower. I think I can tell the difference between 10Hz and higher frequencies.